Control circuits for selecting systems



Aprll 13, 1954 B. s. CAHILL 2,675,537

CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 30, 1952 6Sheets-Sheet l 9 33 I6 RELEASE SOLENOID MASTER STA.

:ELEcra/a sun /3 DRIVE RELAY m A .2 o I. I0 3 IO M A $74. 4

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CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 50, 1952 6Sheets-Sheet 2 RELEASE SOLENOID FIG. 3 E sr,4 r/o/v I I09 sum.

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DIV-OFF INVENTOR BERNARD S. C'AH/LL April 1954 B. s. CAHILL 2,675,537

CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 30, 1952 6Sheets-Sheet 5 RELEA s5 SOLENOID F G. 4 STATION 2 '-D E1416. 1 (ALL uLL)awe-EN M ,/04 M g 1150 w T/ME DELAY 9 F be RELAY /s I SYN M540 TOR W NERROR 24 -z4 RELAY Y Z7 27 2a ii .a/ v 32 v 32 April 13, 1954 B. s.CAHILL 2,675,537

CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 30, 1952 6Sheets-Sheet 4 26 aa 3/ l 32 nuns: SOLENOID FIG. '5 5 TA T/ON 3 GREENTIME DELAY RELAY A TTORNEY April 13, 1954 B, 5, c 2,675,537

CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 30, 1952 6Sheets-Sheet 5 FIG. 6

a2 7/ ma '.1-/ if INVENTOR BERNARD S. CAH/LL i rv I I A TTORNEV April13, 1954 B. s. CAHILL 2,675,537

CONTROL CIRCUITS FOR SELECTING SYSTEMS Filed July 50, 1952 6Sheets-Sheet 6 FIG. 7

INI/L NTOR BERN/4RD 5 CA H/L L 8V & ATTORNEY Patented Apr. 13, 1954UNITED STATES PATENT 2,675 537 OFFICE CONTROL CIRCUITS FOR SELECTINGSYSTEMS Illinois Application July 30, 1952, Serial No. 301,748

8 Claims.

This invention relates to signaling systems and particularly toselecting means for remote control of electrically operated apparatus.

The object of the invention is to provide an economical, rugged,reliable and simple remote control selecting means which may be employedfor a variety of purposes and bring the advantages of certainconventional but highly developed and costly selector systems into moregeneral use.

Reference is hereby made to application, Serial Number 301,666, filedJuly 30, 1952, in the name of Davidsmeyer et al. and application, SerialNumber 30 ,711, filed July 30, 1952, in the name of Stanley Schlaf forthe disclosure of various, separate and distinct inventions made in thedevelopment of a selecting system embodied in identical disclosures inthe present application and the said other two applications.

The invention, in essence, resides in the use of start stopdistributors, common in the printing telegraph art, activated bysynchronous motors similar to those employed in the ubiquitous clockwhich depends on the present day precise regulation of th frequency ofthe commercial electric power supply in substantially all communities.Through the use of such motors a selecting system need not be confinedto any one location where the same power supply is available to driveall the start stop distributor motors but may embrace an extensive areaincluding a number of different power sources and be operated over aline long enou h to be classed as a toll or long distance line. Theselecting system may be used for telecommunication purposes, as forselectively enabling any one or more of, or combination of, stationseach provided with telecommunication apparatus so that these selectedstations may be enabled. The selecting system may be used for releasingany previously enabled station or combination of stations and forsetting up a new combination. In such a use a master station and aplurality of outlying stations may be joined in a conventional ringcircuit over which the selection may be made and the telegraph messagemay thereafter be transmitted.

It will be understood, however, that the present invention is notexclusively used for telecommunication purposes but may b employed for awide variety of purposes where a selection and operation of one or moreof a plurality of stations for any purpose is desired. The invention maybe used for such simple purposes as the selective operation of callsignals such as lamps, buzzers or bells or for the more complicatedpurposes of remote control of machinery.

A feature of the invention is the use of small synchronous motors fordriving the start stop distributors, operated from local commercialalternating current mains, the said commercial means started andmaintained in operation by supplies at different locations having oncommon characteristic, namely a precisely regulated frequency,substantially of the same value at all locations. It will be found inpractice that often the alternating current supply used for the variousstations is one and the same, in other cases that a common source ofprecisely regulated frequency is employed by different electricitysupply companies for a reference standard and in still other cases thatcommercial demands lead to great accuracy in the maintenance of thefrequency characteristics of the supply so that the commercial supply atall points wher stations for a system of the present invention may beinstalled are completely adequate to cause the various distributors ofthe system to operate synchronously. In accordance with this feature, itis to be particularly pointed out that, highly accurate regulation ofthe frequency while desirable is not necessary, for the tolerances inthe operation of the distributors are wide and since any singleoperation is of only a few seconds duration, synchronism in theoperation of a plurality of these motors is sufiiciently accurate evenif the regulation of the frequency of the sources is entirely inadequatefor the purpose of driving the household clocks. Substantially uniformfrequency for operating the motors of the system is suflicient.

A feature of the invention is a time measuring a manually operable meansfor enabling the signaling means, which may therefore be eliectivelystarted only if the said manually operable means is held operated over aminimum predetermined period of time. Since the system of the presentinvention is constructed and arranged to operate over a circuit employedfor other conventional signaling means, this time delay is introduced asa means for difierentiating from the same type but generally shorterduration signals employed by such conventional means. By way of example,the system of the present invention may be operated over a conventionalprinting telegraph .ring circuit having a plurality of printingtelegraph stations serially connected and must be rendered unresponsiveto the printin telegraph signals.

In accordance with this feature each synchronous start stop distrilbutorstation is provided with a constantly operating synchronous motor, thesources of alternating current at the various stations not beinnecessarily the same nor in phase with each other but substantially ofthe same frequency so that the various motors will operate atsubstantially the same speed. Advantage is taken of the fact thatpractically all localities now have a standard 60 cycle commercialsupply, which be used for timing purposes in the operation of thepresent invention and thus eliminate other intricate and costly timinapparatus.

constituting a slow operating relay.

after a predetermined period of time and which are driven by a constantspeed motor. A coil for clutching these contacts to the constantlyoperating motor is provided so that upon energization thereof thecontacts are started in operation and through the movement of the motorare caused to come into contact to close any given circuit after thelapse of a given period, by way of example, threehundred milliseconds.By the use of such a relay the unlatching of the distributor may bedelayed for a period of time greater than any conventional signal whichmay be transmitted over the common circuit.

Another feature of the invention is a relay having a coil and aconstantly rotating core, an armature suspended above said core adaptedupon the energization of said coil to be brought into frictionalengagement with said core for rotation and carrying a contact piecebrought by the rotation of said armature into cooperative relationshipwith a stationary contact, said armature beingsuspended on a springwhich on deenergization of said coil will return said armature and itscontact piece to their normal positions.

Another feature of the invention is a noncumulative slow operatingrelay, in other words one which will require a definite andpredetermined period of time in which to effect an electrical contactbut which cannot succeed in closing such a contact on a repeatedsuccession of energizations each of less than the said predeterminedperiod. This relay is constructed and arranged to release to its normalposition at high speed so that in effect it responds to a train ofimpulses by starting its contact closing movement on each impulse fromits starting position and will not build up to an operated position onanything less than an impulse equal to or greater than the saidpredetermined duration.

Still another feature of the invention is .a relay in which the contactsmove slowly and at .a uniform rate to. an operated position upon theenergization of the coil thereof but which release and move back totheir normal position a high rate of speed.

Another feature of the present invention is the use of a plurality ofstart stop distributors in a series circuit so that the circuit is,during the simultaneous operation of the said plurality of distributors,periodically closed again into a single series circuit as all thedistributors simultaneously pass over corresponding segments. With theexception of the master station, from which the selection is controlled,some sort of circuit is completed through each station for every segmentof its distributor. In general a relay coil of a function relay isincluded in the circuit of a different one of the function segments ateach station and the remainder of the function segments lead in commonthrough the coil of a relay incidentally used for signaling theinformation that some other station has been selected and enabled. Wheresuch signalled information is not needed this common coil mustnevertheless be used but will perform no other function than to providea closed path through the station so that the function relay at someother station may be operated. In accordance rality of start stopdistributor means whereby,

with this feature the ring'circuit includes a single conductor in seriesrelationship with a pluduring the simultaneous rotation of saiddistributors a plurality of derived circuits are sequentiallyestablished. Since a function relay may be included in each derivedcircuit, one at each of said different stations, any one or more of saidstations may be selected by effectively closing the correspondingderived circuit or circuits at. a master station.

In accordance with this feature accuracy in operation may be gained atthe expense of time and thus provide a selecting system somewhat slower.in operationthan other highly developed conventional systems butnevertheless of rugged and dependable operation so that an economicaldevice is provided for a field requiring a selecting device but whichcould not economically justify conventional apparatus. By the use ofcomparatively slow operating synchronous motors powered by thewidespread and precisely regulated commercial electric supply sources, a

plurality of start stop distributors may be 'dependaoly placed in seriesand may dependabl'y sequentially close a plurality of circuits so thatif one of such circuits is marked for operation it may be usedefiectively for a selecting operation. It must nevertheless beunderstood that the principle of the invention is applicable tohighspeed systems as well as to the comparatively slow speed systemherein disclosed by way of example. It will be understood that theeconomy of the system, however, has a degree of control over the speedemployed, and while the principle of a plurality of start stopdistributors in series may be perfectly feasible for a high speedsystem, the cost of the more precise control necessary for such speedoperation probably could not be justified for the field of use of thepresent means.

Another feature of the invention is an arrangement for automaticallyrestoring all stations to normal as a first step in a selectingoperation. The system of the present invention is known as a push buttonselector system and is characterized by the use of a conventional typeof push button arrangement whereby the setting of a given buttoncorresponding to-a wanted station or combination of stationsautomatically and mechanically releases any other button theretoforeoperated. In addition each station is provided with a releasing or cutoff relay for restoring the station circuit to normal and all thesereleasing relays are included in the first derived circuit so that whenthe distributors have been started on a round the first operation is areleasing operation thus restoring all stations to normal and puttingthem in proper condition for the immediately following selectingoperation, that is the operation of the function relay at the selectedstation or stations and the operation of a guard relay at all otherstations.

A feature of-the invention may therefore be stated as a selector systemcontrol means which performs a double function on each selectingoperation, (1) that of releasing any one or more of the selectorspreviously enabled and (2) that of enabling any one or more selectorsfor a present operation. When the operator at a master station makes .aselection he does so by actuating any given one or more of thepushbuttons provided and then operates his start key. distributorsrotate. one of the first derived-cir- A the cuits closed is a clear outor release circuit which acts to release any selector previously lockedin circuit.

Another feature of the invention is what has been termed an errorcircuit, that is a safety means for preventing erroneous operation ofthe devices of the present invention. The circuit in question consistsessentially of a means by which an operation started by a manualoperation is completed automatically and without interference by anysucceeding manipulation of the means used for the original manualoperation. This circuit may be considered as a control means, triggeredinto operation manually but, after being so triggered, beyond anyfurther manual control.

In accordance with this feature, and particularly where the timemeasuring means is employed to prevent the starting of the start stopdistributor until a period of time greater than that necessary forcertain conventional signals has elapsed, a start key is provided. Thismay be manipulated by an operator but must be maintained in operationuntil the distributors have been started. If released prior to thatinstant the apparatus will be returned to normal without further effect.However, if held in operation for a longer period, the error circuitwill be triggered and the control will be removed from under any furtherinfluence of the start key.

In one respect the start key will have continued control for by itsmanipulation it provides a looking circuit for the error circuit andtherefore serves as a means to lock in the triggered error circuitwhereby the continued or prolonged operation of the start key actuallyserves as a protection against any ill effects of such a prolongedoperation. Essentially, therefore, the so-called error circuit providemeans to insure a complete and proper operation of the selecting meansand prevent any mutilation of the signals therein. A feature of theinvention may therefore be stated as the combination of a start key, ameans for starting a device in operation under control of said key, anda means responsive to a movement of said device for locking saidstarting means under joint control of said key and said device.

In accordance with this feature means are provided to insure theautomatic and complete restoration of the distributors at all stationsas a preliminary to a selecting operation. It will be noted that aselecting operation is started by an opening, by the start key, of theseries circuit extending through all the stations whereby all the linerelays are simultaneously released and which therefore allsimultaneously close the local circuits for operating the latch magnets.Each distributor starts its operation and each therefore operates itsoff normal contacts which results in the operation of a trigger relaywhich in turn opens the circuit of the latch magnet. This trigger relay,hereinafter also called the error relay, then locks to the back contactof the line relay so that it is now under the joint control of the offnormal contacts and the line relay and therefore cannot release andeffectively establish a circuit for the latch magnet. As eachdistributor reaches its home position it is stopped by its latch and byvirtue of having reached its home position operates it off normalcontacts to a position to release the trigger relay. This relay,however, remains operated so long as the line relay remains released aswhen the operator is slow in releasing the start hey. Again the seriescircuit cannot be completely closed and therefore no line relay can beenergized again until each and every one of the distributors has reachedit home position. Hence the error circuit provides a means for insuringsynchronization of the system.

Another feature of the invention is a means to stop definitely eachdistributor on the completion of each rotation and hold it latchedawaiting a succeeding manual start operation. In accordance with thisfeature the distributors cannot be operated continuously by the merecontinued operation of the start key but must perforce end theiroperation at the end of one complete rotation and remain latched untilthe start circuit is released or reconditioned by a release of the startkey prior to another operation thereof.

Another feature of the invention is a means for automatically releasingthe latch of a disributor immediately that it has been operated to allowthe distributor to start its movement so that the latch will be returnedto its normal position and in readiness to stop the distributor at theend of a complete rotation thereof. The above described error circuitprovides a locking means for the present means, whereby furtheroperation of the distributor latch is inhibited until all parts of thedevice, including the start hey have been returned to normal.

Other features will appear hereinafter.

The drawings consist of six sheets having nine figures, as follows:

l is a block diagram showing how Figs. 2, 3, 4 and 5 may be placed toform a complete schematic ci cuit diagram of a system according to thepresent invention;

Fig. 2 shows a schematic circuit diagram with the apparatus used at atransmitting station shown schematically and partly in section;

3 show a similar schematic circuit diagram for one of the plurality ofreceiving stations and having the apparatus thereat shown in skeletonform with the parts thereof placed in the same relative positions asshown in Fig. 2;

Fig. 4 is a similar schematic circuit diagram;

Fig. 5 is a similar circuit diagram showing also 7 a block indication ofother stations which may be included in the circuit;

Fig. 6 is a side View, much enlarged, of the apparatus including thedistributor and the means by which it is operated;

Fig. 7 is a vertical section of part of the apparatus shown in Fig. 6;

Fig. 8 is a top view showing details of the latch and the manner inwhich the distributor arm may be released and allowed to operate, and

Fig. 9 is a skeleton schematic circut diagram showing an alternativecircuit arrangement which may be used at the various stations of thesystem, whereby the distributors may be started immediately withoutwaiting a specified time.

In each of Figs. 2, 3, 4 and 5 a source of sixty cycle alternatingcurrent is shown. These various sources may be one and the same or theymay be entirely independent sources depending.

on the location of the various stations. Each is shown as a source of117 volt alternating current, thus indicating a commercial supply. it isnot necessary that these voltages be exactly alike since by the use ofsuitable transformers the supply for the different stations of thesystem may be regulated in well known manner. t is necessary, however,that the frequency characteristics of these various sources besubstantially or reasonably the same. It will be noted in Fig. 2 thatthe source of supply I is connected through a fuse 2 and a switch 3 to apair of conacme-e7 duotors leading "through the jack and plug device tothe winding ofa synchronous motor 4 so that this synchronous motor willbe constantly rotating. Also this source of supply is connected by atransformer through-a rectifier '6 and a network consisting of animpedance element 1 and a condenser 8 to form a suitable supply ofdirect current for the operation of the relays'and other apparatus ofthe system. In each of Figs. 2 to 5 inclusive there is shown a jack andplug arrangement having thirty-two cooperating elements. This is aconvenience since it renders it possible and easy to take the devicshown in Figs. 6, 7 and 8 out of circuit for repair, adjustment orreplacement. It will be understood that this jack and plug device is notnecessary to the proper functioning of the apparatus but is, as ahovestated, employed as a convenience.

At the top of Fig. 2 a battery 9 (which may also be derived from thecommecial source) is shown, which supplies current in a loop circuitwhich may be traced in detail through the jack and plug (23), the ringof the distributor I0, the'brush i I thereof in its normal arrestedposition-th stop segment t2, the plug and jack (21), the start switch'13, the drive relay M, conductor l5, jack and plug (23) of thestation'n-umber shown in Fig. 3, ring l'i-of the distributor thereat,brush i3, start segment 19, plug and jack (21), drive relay 2!),conductor 2!, jack and plug (23) of station number 2 shown in Fig. 4,ring 22 of thedistributor thereat, brush 23, start segment 24, plug andjack (21), drive relay 25, conductor 26, jack and plug (23) of stationnumber 3 shown in Fig. 5, ring 2? of the distributor thereat, brush 28,start segment 29, plug and jack (21), drive relay 3U, conductor 3|,thence through other stations 32 and finally back over conductor 33 tothe battery 9. Since this circuit is closed, all of the drive relaysincluded therein, such as the DR relay It, th DR. relay 26, the DR.relay 25 and the DR relay 30 will be energized and therefore willmaintain .an open contact at their armatures.

All of the synchronous motors at the various stations will be operatingand since the frequency characteristics of all the various "sources ofalternating current are substantially the same these motors will beoperating at the same speed. Looking at Fig. 2 it will be seen that theshaft of the motor has secured to it a. magnetic piece as whichconstitutes a core for-a relay whose coil 35 is cooperatively associatedtherewith. An armature for this relay consists of a magnetic disc 36which is supported by a coiled spring 531 in such a manner that itfloats a short distance abov the core 34 but is not attached to theshaft 38 of the motor. When the coil 35 is energized the armature (it isattracted to the core 34 and, making frictional engagement therewith,begins a rotary movement in the direction of rotation of the motorindicated herein as clockwise. Attached to the armature 38 there .is acontact piece 39 which will approach and finally make contact withanother contact piece 46.

At its upper extremity a cup shapedpiece 4| .is attached to the shaft 38of the motor l and rotates constantly therewith. A disc i2 having nomechanical connection with this cup is shown as being placed therein andin accordance with this invention is immersed in a =fiuid 43. The shaft45 terminates in a latch is which is normally held stationary'by theelement it'of a solenoidli 'i. Therefore the cup M constantly rotatesbutthedisc 42 remains stationary.

The physical characteristics of the fluid 43 are =s-uch that :the cup eamay-constantly rotate while the disc 52 remains stationary without unduedrag on the motor. This constitutes a fluid'clutch and when the element'46 is Withdrawn from the latch-45 thedisc 42 will immediately begin torotate with the cup 4! withpractically no slippage between the two.

The fluid used in this clutch may varyover-a wide range. -Oneo.f themost suitable is :oneof those chemical compounds knownasa silicone, theparticular one being dimethylpolysiloxane,an organic compound composedof long chains-of carbon, hydrogemoxygen and siliconatoms-linkedrepetitivelyin .a diagram typical of complex .organic compounds. Thishas a viscosity of 30,060 centistokes, a viscositycoefficient of .61,a.freezing point of -44 Csand a boiling point :of 200 C. It=lSz0fparticular value in its present application because it maintains itsviscosity values over .a wide range-of temperatures for longperiods oftime-exhibits true Newtonian .flow characteristics, is relatively inertto materials used in the present device, has good lubricating qualitieswhen used :in the presentmannerand is readily available commercially notonly with the-constantsabove statedbut in a wide range of axiscosities.

The invention, however, is :not limited to the use of this one fluid butincludes the use of other fluids of similar physical characteristics,such as certain petroleum oils having suitable temperature-viscositycoefficients.

There is a cam as attached to the shaft 4d so that as soon as the shaftas leaves its normal position a connection will be made between the ofi?normal springs wand 50.

These arrangements may be seen in Figs. 6, '7 and'8 substantially in theform in which the device is manufactured. Here it will be seen'that abaseplate 5| forms an element to which the other parts are secured. Themotor 52'is-shown-sccured to the base-plate 5| by means'of the :standofi posts'5'3 and 5 3. The shaft 55 of the motor is seenas'extendingupwardly, particularly in Fig. 7. The magnetic piece 56secured to the-shaft .55 forms a constantly rotating core for a relaywhose-coil 5-! is-encased ina magnetic'shell- 58. By-meansof a pairofstand off posts 55 andto a circular insulating element 6! is supported.Around the periphery of this circular piece there are a plurality-ofcontactpieces, such as the contact pieces 62 and 63 pictured in Fig. 6.Thecontact piece 64 indicated in Fig. 8 is the stop segment oftheudistributor.

Attached to the shaft 'E-Eat its upper-end there isan element .65 towhich is attached a disc 66. A circular acup like element 67 ofinsulating material is placed over the element $5 and by means of an Oring or elastic torus G8 the connection between the elements 65 and "5!is made fluid tight. A third or cap element :69 also of insulatingmaterial issecured to the cup element 6-! so as to forma reservoirtherebetween in which a disc 65 may rotate. The element 65! has anarrowring portion or bearing surface on the plate :56 to maintain a properdistance between the upper surface of the element 69 and the ,plate .66.The space within the-reservoir is filled with-a viscous fluid havingphysical characteristics which will allow the disc 66 to rotateconstantly without placing an undue drag on the motor and yet whichlwillimpart the motion of the motor :and the disc 6!; to the reservoirdeviceiormed'of the elements :57 and 69 when-the latch is released.

There is a ring of metal 10 secured to the underside of the element 61on which a brush 1i constantly bears so that an electrical connectionmay be made between the brush H and the ring 10 in all positionsthereof. At one point the ring 10 is extended and bent downwardly as at12 and to this a brush 73 is secured which will bear on the faces of thevarious segments shown. In Fig. 8 the clutch magnet 74 is shown carryingat the end of its armature a shear 15 which engages the portion 12 ofthe distributor brush and holds it against rotation. It will be notedthat when the magnet 74 is energized the shear 15 will be moved to theright and out of engagement with the brush portion 72 so that at thistime the fluid clutch will become active and cause the brush E3 to makea complete revolution, making contact in turn with each of the segmentsof the distributor.

Attached to the insulating circular piece there is a member 16 to whicha spiral spring '1'. is secured. The spring H is attached at its otherend to a magnetic armature i8. The spring 11 is so formed that it willhold the magnetic part it in the position shown in Figs. 6 and '7, thatis, floating a short distance away from the constantly rotating core 56.There is attached to the armature 18 a contact piece 19 having a bent uptab 89 resting against a stop 8|. When the coil 51 is energized themagnetic piece 18 will be attracted downwardly so that it comes intofrictional engagement with the constantly rotating core 55 and rotatestherewith until the contact piece 79 comes into engagement with thestation ary contact piece 82. By means of an adjusting K screw 83 thenormal distance between the contact piece 19 at rest and the contactpiece 82 may be adjusted so that in practice all of the various timedelay or slow operating relays will make the connection between thepieces 19 and 92 simultaneously.

The top portion of the cap piece 69 is generally circular in shape buthaving a segment cut off as shown in Fig. 8 so that the off normalspring 84 may be operated shortly after the beginning of the movement ofthe brush 13.

Going back now to the circuit diagram shown in Figs. 2 to 5 inclusivethe operation of the device may be described as follows. Disregardingthe actual selecting operations for the present it may be noted thatwhen the fundamental circuit fed by the battery 9 is opened by means ofthe switch I3 the DR relay [4 is deenergized. Thereupon a circuit willbe established from battery leading from the rectifier 6 through thearmature and back contact of the DR relay [4, the armature and backcontact of the ER trigger relay 85, the solenoid of the time delay relay35 to ground. The armature 36 will thus be attracted to the constantlyrotating core 34 and the contact piece 39 will move toward the contactpiece 49. When contact between these pieces is made a circuit isestablished from battery through the winding of the release solenoid 41,the spiral spring 3?, the contact piece 39, the contact piece 49 toground, whereupon the latch 45 is released and the brush H under theinfluence of the fluid drive clutch begins to move over its segments.

The system shown in Figs. 2 to 5 inclusive and employing the time delayrelay is useful in a system where the 100p circuit is also employed forthe transmission of other signals such as printing telegraph signals.The time delay relay would respond to such signals but would restoreafter each so that even a train of such signals 10 would fail to startthe distributor. In this system the start switch must be held open for aperiod of time long enough to cause the time delay switch or slowoperating relay to close effectively its contacts.

If the start switch l3 has been maintained open and therefore the DR.relay M has remained deenergized until this circuit for the solenoid 41is made, the latch 45 will be released as described. Almost immediatelythe off normal contacts 49 and 5t! are made so that a circuit isestablished from battery, the contact 58, the contact 49, the ER relay$5 to ground. This trigger is now held energized in two circuits, onefrom battery through the armature and back contact of the DR relay i i,the armature and front contact of the ER relay 85, the winding thereofto ground, and the other from battery through the off normal contacts51? and 4&3, the winding of the ER relay to ground, so that this ERrelay will remain energized at least until the brush II has completed acycle to the point where it has been stopped by the clutch element 46.If, during its cycle, the start switch 13 has been released so that whenthe brush H again reaches its start contact I2, the DR relay M will beenergized and the ER. relay 85 will be released from its lockingcircuit. If the start switch l3 has not yet been released then the ERrelay 85 will remain locked up even though the brush H has completed acircuit of its segments and been latched into its normal position. Itwill also be noted that upon the first operation of the ER, relay 85 thecircuit for the solenoid 35 of the slow operating elay is opened so thatthe armature 39 thereof is released from frictional contact with therotating core 3 and under the influence of the spiral spring 3'17 willreturn to its normal position, thus opening the circuit of the releasesolenoid 41. It will thus be seen that immediately after the contact 39has come into engagement with the contact 40 that the release solenoid41 will be opened and the circuit completed by the slow operating relay3% will be opened.

It will be understood that the arrangements at all the other stationsincluded in the loop circuit are exactly the same. Therefore, when thestart key is is operated all of the drive relays i4, 29, 25 and 30 willbe simultaneously operated, the slow operating relays at each of thesestations will begin to operate and they will simultaneously close theircontacts so as to start simultaneously the brushes ll, I8, 23 and 28.Thus the distributors will operate simultaneously and each of thebrushes will make contact with corresponding segments simultaneously. Inthe drawings, Figs. 2 to 5 inclusive, segments 20 and M are connectedtogether and constitute stop circuit segments. Segments 22 and I5 arealso connected together and in turn connect to the conductor it so thatas the brushes 1 l, i8, 23 and 28 come into contact with their segments22 a derived path release circuit will be established from the battery,the ring 88 of the distributor, the segment 22, the conductor l tthrough similar circuits at the other stations each including a clearout relay such as the C0 relay 86 at station number I, the CO relay 81at station number 2 and the CO relay 83 at the station number 3. Theseclear out relays have their armatures connected to ground to which thevarious function relays are locked. Assuming, by way of example, thatthe function relay 89 has been operated and locked in a circuit frombattery, its armature and front contact, its winding, the back contactand armature of the CO relay 8-5 to ground, then it will be seen that bythe operation of the CO relay to the function relay 89 may be released.Thus, as the distributors at the various stations are started the firstaction taken is to release any and all relays which have been lockedinto position by some previous operation of the receiving station.

Each station has thereat one or more function relays such as thefunction relay 8%). ihis relay may be energized as at station i when thedistributor it comes to its segments 2 and 3 providing the switch 96 atthe transmitting or master station has been operated. Therefore, as alldistributor brushes reach their number 2 segment a derived circuit willbe established. including the operated all call selecting push button99, the FTP. relay 9i at station number the FTR relay 92 at stationnumber 2, the FTR relay 93 at station number 3 and similar circuits atthe other stations indicated by the box 32. Upon the operation of theFTR relay 9i a circuit is established from battery, the armature andfront contact of the FTR relay 9!, the winding of the FR relay 89, theback contact and armature of the CO relay 3% to ground. The FR relayresponds and locks in a circuit from battery, its armature and frontcontact and its winding to ground over the circuit just traced. The FRrelay will therefore remain locked until it is released by thetransmission of another selecting signal. In this derived circuit,including the segments 2 and 3 of each of the distributors, all of thestations are called in. As another example, if the push button 9 hasbeen operated then no one of the FTP. relays 9 i, 92 or 93 would havebeen operated, but instead the FIR relay 85 at station number i would beoperated when the brush i 3 reached its segment l. At station number 2the segment number 4 is connected to the LTR relay 96 and at stationnumber 5 the segment number 5 is connected to the LTR relay 8'? so thatat station number i a function relay will be operated whereas at all theother stations the LTR relays will be operated. At station number i thenthe FR relay 98 will respond while at station number 2 the LR relay (-39and at station number 3 the LR relay 598 will respond. These relays willlock in the manner described.

The function relays ilay be used for any desired purpose. As shownherein, merely by way of example, the function relay 98 will close acircuit for a bell iti which may be trace from one side of thecommercial source of alternating current through the bell H35, the frontcontact and armature of the FR relay $8, the back contact and armatureof the LR relay N32 to the other side of the commercial source ofsupply. At the same time a connection will be made in parallel with thebell it! for the green signal lamp N33 to indicate that at this stationa selection has been made. At each of the other stations where the LRrelays are operated a connection will be made through the red signallamp 104 at station number 2 and 5'35 at station numher 3 thence throughthe front contacts and armatures of the respective LR relays to thesource of supply. Thus at one station the green lamp Hi3 will be activewhile at all the other stations the red lamp will be active.

If, on the other hand, the push button 596 had been operated then the FRrelay it? at station number 2 would have been operated when the variousdistributors reached the number 8 segments.

It should be noted that each of the function relays such as the FR relayBB at station number i, the FR relay it? at station number 2 and the FRrelay its at station number 3 will control motors, such as the motor itsat station number i, the motor llii at station number 2 and the motorill at the station number 3. These are indications that the motors ofprinting telegraph apparatus may be started so that as a result of thisselection such printing telegraph apparatus may be enabled.

Throughout the drawings Figs. 2 to 5 inclusive, two segments have beenconnected together to form substantially a single segment for thepurpose of making selections. This arrangement may be used in a systemwherein there are only a small number of stations for the purpose ofgiving wide latitude in the operation of the devices. It should bedistinctly understood, however, that this is not necessary and that eachsegment may be used for a separate derived circuit.

The switching arrangement shown in Fig. 2 may be such that the variouspush buttons are mechanically interlocked. By a conventional arrangementof this lrind Whenever any one of the push buttons, such as $8, isoperated it will mechanically release any other button which has beenoperated previously. Each of the function buttons, such as the button 9%and those shown below, are arranged so that when pushed they will remainoperated thereafter. Another button, shown at the top and numbered H2,is known as a selector release switch. This button when pushed willmechanically release any other of the selecting buttons but will notitself remain operated. However, it will perform the same function asthe selector start switch i3 thus opening the circuit and starting thedevices as hereinbefore described.

Fig. 9 is a thumb nail sketch of an alternate circuit arrangement inwhich no time delay is employed. The system may be constructed with thiscircuit leaving out entirely the slow acting relay where the system willnot be employed to transmit any other than the selecting signals. Thus,in Fig. 9 the fundamental circuit is shown as a conductor H3 passingthrough a start key lid and a DR relay 5 [5. As in the main circuitdiagram the DR relay i it is constantly operated until the circuit isopened means of the start key ii l. At this time a circuit will then beclosed from battery, the armature and back contact of the DR relay 5iii, the armature and back contact of the ER relay Ht through the latchmagnet or release solenoid I H to ground. Under this condition thedistributor will be started immediately, whereupon the oif normalcontacts lit will close and cause the operation of the ER relay H5. Thisrelay will then lock in a circuit from battery, the armature and backcontact of the DR relay H5, the armature and front contact of theERrelay Hi3 and will remain in this condition until both the off normalcontacts I it are opened and the DR relay 1 i5 is again operated.

What is claimed is:

1. In a signaling system, a selector having a start stop distributor, acontrol circuit therefor comprising a normally closed circuit includinga normally operated relay and a manually operated switch for openingsaid circuit, a latch means for said distributor, said latch means whenenergized operating to free said start stop distributor for operation, acircuit for energizing said latch means closed in the released positionof said normally operated relay, another relay having contacts in serieswith said latch energizing circuit, said contacts being normally closedin the released position of said other relay and opened in the operatedposition thereof, off normal contacts controlled by said distributor, acircuit for said other relay controlled by said 01f normal contacts anda locking circuit for said other relay controlled by said first relay,Whereby said other relay operates to deenergize said latch meansimmediately after said distributor has moved off normal and will remainoperated thereafter until (1) said distributor has completed anoperation and returned to normal and (2) said first relay has becomeenergized.

2. In a signaling system, a selector having a start stop distributor, acontrol circuit therefor comprising a normally closed circuit includinga normally operated relay and a manually operated switch for openingsaid circuit, a latch means for said distributor, said latch means whenenergized operating to free said start stop distributor for operation, aslow operating relay for energizing said latch means, a circuit for saidslow operating relay closed in the released position of said normallyoperated relay, another relay having contacts in series with said slowoperating relay circuit, said contacts being normally closed in thereleased position of said other relay and opened in the operatedposition thereof, off normal contacts controlled by said distributor, acircuit for said other relay controlled by said off normal contacts anda locking circuit for said other relay controlled by said first relay.

3. In a signaling system, a selector having a start stop distributor, aconstantly operating synchronous motor for operating said distributor, acontrol circuit for said distributor comprising a normally operatedrelay and a manually operated switch for opening said circuit, a latchmeans for said distributor, said latch means when energized operating tofree said start stop distributor for operation, means constituting aslow operating relay for energizing said latch means, said meanscomprising contacts driven by said motor to a closed position at the endof a predetermined period of operation of said motor, a circuit for saidslow operating relay closed in the released position of said normallyoperated relay, another relay having contacts in series with said slowoperating relay circuit, said contacts being normally closed in thereleased position of said other relay and opened in the operatedposition thereof, ofi normal contacts controlled by said distributor, acircuit for said other relay controlled by said ofi normal contacts anda looking circuit for said other relay controlled by said first relay.

4. In a signaling system, a distributor, a latch for holding saiddistributor against movement, a latch magnet for moving said latch tofree said distributor for movement, off normal contacts for saiddistributor, a circuit for said latch magnet including a start key, arelay responsive to said start key, a trigger relay responsive to saidof)? normal contacts, a locking circuit for said trigger relaycontrolled by said start key responsive relay and contacts in said latchmagnet circuit operated by said trigger relay.

5. In a signaling system, a single conductor series circuit including aplurality of stations each having distributor means for effectivelyincluding a different derived circuit in said series circuit at eachsegmental position thereof, each said distributor having a normalresting position and a segment therefor and a plurality of functionalpositions and a separate segment for each said position, one of saidstations including a plurality of normally open push button switches ineach of said functional positions for selectively closing said derivedcircuits, a means included in said series circuit and connected to saidseg ment for said normal resting position for said distributor foropening said series circuit, means responsive to said circuit openingmeans for start ing all of said distributor means, means responsive tothe movement of all said distributor means to other than said normalresting positions for eliminating said starting means from said seriescircuit.

6. In a signaling system, a plurality of distributors serially includedin a signal circuit, a line relay in series in said circuit for eachsaid distributor, a latch for each said distributor, a latch magnet foreach said distributor, off normal contacts for each said distributor, atrigger relay for each said distributor, said trigger relay beingresponsive to said ofi normal contacts, a locking circuit for saidtrigger relay controlled by back contacts of said line relay, a circuitfor said latch magnet controlled by said trigger relay and a start keyfor simultaneously deenergizing said line relays.

7. In a signaling system, a plurality of distributors serially includedin a signal circuit, a line relay in series in said signal circuit foreach said distributor, a latch for each said distributor, a latch magnetfor each said distributor, off normal contacts for each saiddistributor, a time measuring device for operating each said latchmagnet after a predetermined period of time, contacts on said line relayfor enabling said time measuring device, a trigger relay for each saiddistributor responsive to said on. normal contacts for disabling saidtime measuring device, a locking circuit for said trigger relaycontrolled by said line relay and means for simultaneously releasing allsaid line relays.

8. In a signaling system, a plurality of distributors serially includedin a signal circuit, a line relay in series in said signal circuit foreach said distributor, a latch for each said distributor, a latch magnetfor each said distributor, ofi normal contacts for each saiddistributor, a time measuring device for operating each said latchmagnet after a predetermined period of time, contacts on said line relayfor enabling said time measuring device, a trigger relay for each saiddistributor responsive to said ofi? normal contacts for disabling saidtime measuring device, a locking circuit for said trigger relaycontrolled by said line relay and means for simultaneously releasing allsaid line relays, and means controlled by said distributors formaintaining said line relays in their released positions until all saiddistributors have again become latched.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,632,106 Zogbaum June 14, 1927 1,645,563 Whistlecroft Oct.18, 1927 1,689,294 Potts Oct. 30, 1928 1,703,152 Kleinschmidt Feb. 26,1929 2,424,571 Lang July 29, 1947 2,567,226 McWhirter Sept. 11, 1951

